In the remote manipulator art, numerous types of "hand" units have been devised for grasping an object to move that object from one location to another, to perform some operational task, etc. Most of these hand units (commonly called "end effectors") are simply a pair of fingers or tongs that move in a parallel relationship toward or away from each other. Typically, these tongs that are to grasp the object have a resilient surface to improve grasping friction, and some units provide for pressure-related feedback to insure proper grasping force.
In order to grasp an object using these devices of the prior art, the device must be seen, either directly or through the use of video equipment, so that a proper grasping location on the object is utilized to minimize inadvertent disengagement. For example, generally spherical objects must be grasped at a major diameter, necked-type objects grasped at the neck, etc. Where objects of a particular configuration are to be grasped routinely, tong units of a configuration matching the object can be used. Highly irregularly shaped objects, particularly those with sloped surfaces, are grasped with only great difficulty, perhaps after several attempts. Further, if the object is unknown in configuration when grasped, it must be directly or indirectly viewed to ascertain its shape. For example, a bolt might be grasped for use in assembling a piece of equipment; however, a view of the bolt might be necessary to ascertain the type of head (hexagonal or square), the length of the threaded portion, etc.
There are applications for remotely operated contacting/grasping devices where the object is only partially seen or even cannot be seen by conventional means. For example, in underwater exploration the murky waters usually encountered prevent any viewing. Also, light distortion hampers exact positioning of the device. Thus, it becomes important that the object be grasped without such exact positioning. Also, it is desirable to obtain information that can be used to deduce the shape of the object that is to be contacted/grasped. The terms contact/grasped or contacting/grasping, etc., as used herein are meant to cover those alternates: just contacting an object for whatever purpose (usually non-moving); and grasping an object with the primary function of motion of the object. Other suitable terms for this operation are "engaging", "engage" and "engaged".
Numerous special configurations of grasping means have been developed, some of which are designed to grasp objects of unusual exterior shape. One such device is described in U.S. Pat. No. 4,572,564, issued to T. M. Cipolla on Feb. 27, 1986. Other typical devices are described in U.S. Pat. Nos. 4,047,709, issued to B. S. J. Thyberg, et al. on Sept. 13, 1977; 4,632,444, issued to M. R. Martinez et al on Dec. 30, 1986; and 4,088,312, issued to NASA on May 9, 1978. None of these devices are adapted for use as a hand of a remotely operated device and none of these, except for '444, provide signals related to the shape of the object contacted/grasped.
Accordingly, it is a principal object of the present invention to provide a hand unit for a remotely operated device, said hand providing a capability to contact/grasp a surface having either a regular or irregular configuration
It is a further object of the invention to provide a device for use in contacting/grasping an object having an unknown surface configuration, the device providing information from which the shape of the object can be obtained.
It is another object of the invention to provide a device which can grasp an object and then reorient the object into a selected new orientation.
These and other objects of the present invention will become apparent upon a consideration of the drawings referred to hereinafter in combination with the detailed description thereof.